Heat conductive ground cover



Sept. 24, 1963 H. LIU 3,105,134 HEAT CONDUCTIVE GROUND COVER Filed Feb. 13, 1962 Hon/en L/u INVENTOR.

United States Patent 3,195,134 HEAT CONDUETHVE GRGUND CGVER Homers Liu, eapolis, Miriam, assignor of fatty percent to Richard H. Qhiu, Provo, Utah Filed Feb. 13, 1962, Ser. No. 172,918 10 Claims. (Cl. 219l9) This invention comprises a novel and useful heat conductive ground cover and more particularly relates to a mat or grid of articulated metallic construction and having concealed and housed therein heating means Whereby to melt snow and ice accumulating thereon.

The primary purpose of this invention is to provide a grid 01' mat having heating means incorporated therein whereby the device may function as a cover for walkways, openings and the like and will effectively melt any snow or ice accumulating thereon.

A further object of the invention is to provide a grid in accordance with the preceding object which shall incorporate therein adequate drainage means to permit discharge of the melted snow and ice.

A further object of the invention is to, provide a grid of an articulated nature having a plurality of elements connected together to permit a limited rocking or flexing movement of the elements relative to each other whereby the grid may readily adapt itself to slight inequalities of the surface upon which the same is placed.

Still another purpose of the invention is to provide a heated grid in accordance with the foregoing objects which shall be provided with laterally extending lugs on the sides of the transverse elements which will maintain adjacent transverse elements in a fixed spaced relation.

Still another object of the invention is to provide an articulated type of heated grid consisting of parallel transverse elements which are connected in pairs at their extremities by fastening means such that the two transverse elements in a pair are rigidly connected against relative movement while adjacent pairs are connected to permit a limited rocking or flexing action therebetween.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of a heat conductive ground cover of griddike configuration in accordance with this invention and utilizing electrical heating means;

FIGURE 2 is a vertical longitudinal sectional view taken substantially upon the plane indicated by the section line Z2 of FIGURE 1 and showing certain details of the spacing lugs and of the heating passages of the invention;

FIGURE 3 is a further detail view in vertical transverse section taken substantially upon the plane indicated by the section line 3-3 of FIGURE 1 and showing more clearly the notched structure of the grid permitting drainage therebeneath together with the disposition of the heat conduits through the elements and the linkage fasteners which connect the elements to each other in the assembled device;

FIGURE 4 is a detail view similar to FIGURE 2 but showing a fluid duct heating means in place of the electrical heating elements in the device; and

FIGURE 5 is an exploded perspective detail view showing the end of one of the transverse elements and the connecting means for adjacent elements and the re taining means for pivoting pairs of elements to each other.

In the accompanying drawings, the numeral 1t} designates generally a mat or grid comprising the heat conductive ground covering of this invention. Obviously the grid may be made of any desired length by merely increasing the number of transverse elements associated therein and of various widths. The grid may be employed either in a manner of a mat upon relatively flat and solid surfaces or as a covering for various trenches or openings as may be desired. The grid functions in use to provide a firm surface upon which persons or objects may pass while effectively dissipating snow or ice falling thereon by means of heat supplied to the grid through heating means embedded therein. Further, the grid provides drainage means so that the water resulting from the melting of the snow and ice may be readily drained away.

In a preferred form of the invention the covering consists of a plurality of transversely extending metal bars 12 which are disposed in a fixedly spaced side-by-side relation to form the entire structure of the covering or grid. Referring now particularly to FIGURES 3 and 5 it will be observed that each of the transverse bars 12 is notched at appropriate places upon its underside as at 14 to thus provide drainage channels extending longitudinally of and beneath the grid with the unnotched portions thus providing support means for the grid. Further, projecting laterally from at least one face of each of the transverse elements 12 is a spacing lug 16 which is adapted to abut against the adjacent surface of the adjacent transverse bar to thus maintain a fixed spaced relation therebetween. As will be noted from FIGURES 2 and 4, longitudinally extending passages 18 extend through the transverse bars 12 and their associated lugs 16 so as to provide in their entirety a conduit or passage throughout the length of the grid which serves to receive therein the heating means for the grid. In the form of FIGURES 1-3, this heating means may consist of suitable electric heating elements 2d. However, in the form of FIGURE 4 the heating element may be in the form of tubes or conduits 22 which may be of a flexible nature if desired, and through which a suitable heating fluid may be circulated. In any event, the heating means serves to impart heat to the internal structure of the grid which is thus distributed by the appropriate arrangement of the heating passages throughout both the width and length of the grid.

As will be observed from FEGURES 2, 4 and 5, each of the lugs 16 has its lower portion convexed or rounded as at 2.4. This rounded surface facilitates a rolling or rocking contact of the adjacent transverse bar therewith so as to maintain the spaced relation but permit a limited rocking or flexing action. Thus, to a limited extent, the grid may be flexed about transverse axes longitudinally of its length in order to enable the grid to readily accomodate or adapt itself to irregularities in the surface upon which it rests.

Referring further now to FIGURE 5 it will be observed that the opposite extremities of each of the transverse bars 12 are provided with a non-circular portion 34 which may be square or rectangular if desired, outwardly of which there is a further extending portion 32 which may be cylindrical in nature. Fasteners are secured to these projecting portions 30 and 32 to retain the transverse bars of the grid in the desire-d assembled relation of the entire covering. 1

Thus, there are provided connecting means in the form of links 34 having therein non-circular openings 36 corresponding to the cross-sectional shape and dimensions of the portion 39. When these links are slidably placed upon the portions 30, they will connect together a pair of adjacent transverse bars in a fixed manner and prevent any relative rotation or twisting therebetween. Thus the two bars are thus rigidly secured in fixed relation. Adjacent pairs of bars which are connected together by the fasteners 34 are retained in assembled relation by means of retainers in the form of plates 38 which have openings 41} therein of the same shapeand size as the cross-sectional area of the portions 32. The retainers 38 thus constitute links which pivotally connect adjacent pairs of rigidly connected bars so that, within the limits permitted by the contact of the curving cam surface 24 of the lug 16 a limited flexing or bending of the mat along its length is permissible.

It will of course be appreciated that the same elements may be assembled together so as to provide a non-flexing mat by merely staggering the pair of connectors 34 at the opposite ends of the transverse bars. In that event, the links -38 will serve merely as retainers to secure and retain the fasteners 34 upon the portions 30.

Alternatively, the portions 32 could likewise be noncircular and the openings 40 in the retainers 38 could be of corresponding shape so as to secure the adjacent pairs of transverse bars together without permitting any flexing movement therebetween.

As shown best in FIGURE 3 the extremities of the outer portions 32 are preferably swaged over or laterally expanded as indicated at 42. Thus the fastener links 34 and the retaining links 38 will be fixedly secured to the end portions of the transverse bars.

In such instances as it may be desired to obtain a top surface of the grid possessing non-skid or increased fric tional properties. The upper surfaces of some or all of the bars 12 may be serrated or otherwise roughened.

The foregoing is considered as illustrative only of the principles of the invention. Further, since. numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is :as follows:

1. A heated covering for walkways and the like comprising an elongated grid including a plurality of transverse bars disposed in side-by-side relation, fasteners connecting the extremities of pairs of adjacent bars in fixed relation, connectors pivotally connecting adjacent pairs of bars, said bars having registering passages therethrough extending longitudinally of the grid, heating means extending through and disposed entirely within said passages for heating said bars to melt snow and ice therefrom.

2. The combination of claim 1 wherein the terminal portions of each of said bars have non-circular portions, said fasteners including links having non-circular openings engaged upon and complementary with said non-circular 4 portions thereby retaining the associated bars in a fixed and rigid relation.

3. The combination of claim 1 wherein the terminal portions of said bars have non-circular portions, said fasteners including links having non-circular openings engaged upon said non-circular portions, said links being each slidably but non-rotatably engaged upon adjacent pairs of links, retainers connecting adjacent pairs together.

4. The combination of claim 1 wherein said bars have laterally projecting lugs for engaging an adjacent bar and maintaining a spaced relation therebetween.

5. The combination of claim 4 wherein said passages extendthrough said lugs.

6. A heated covering for walkways and the like comprising a grid including a plurality of transverse bars disposed in side by-side relation, fasteners connecting the extremities of adjacent bars in fixed relation, said bars having passages therethrough extending longitudinally of the grid, heating means extending through said passages for heating said bars to melt snow and ice therefrom, said bars having laterally projecting lugs for engaging an adjacent bar and maintaining a spaced relation therebetween, said lugs having rounded surfaces engaging the adjacent surface of an adjacent bar to facilitate relative rocking movement of said bars While maintaining said spaced relation whereby to permit limited flexing of said grid.

7. The combination of claim 6 wherein said passages extend through said lugs.

8. The combination of claim 7 wherein said bars are notched on their undersides to provide drainage clearance beneath said .grid.

9. The combination of claim 1 wherein said bars have laterally projecting lugs for engaging an adjacent bar and maintaining a spaced relation therebetween, said bars being notch-ed on their undersides to provide drainage clearance beneath said grid.

. 10. The combination of claim 1 wherein said bars are notched on their undersides to provide drainage clearance beneath said grid.

References Cited in the file of this patent UNITED STATES PATENTS 1,448,907 Bell Mar. 20, 1923 2,231,251 Chaney Feb. 11, 1941 2,497,998 Lee Feb. 21, 1950 2,523,876 Nordstrom Sept. 26, 1950' 2,750,487 Hynes June 12, 1956 FOREIGN PATENTS 543,261 France May 31, 1922 

1. A HEATED COVERING FOR WALKWAYS AND THE LIKE COMPRISING AN ELONGATED GRID INCLUDING A PLURALITY OF TRANSVERSE BARS DISPOSED IN SIDE-BY-SIDE RELATION, FASTENERS CONNECTING THE EXTREMITIES OF PAIRS OF ADJACENT BARS IN FIXED RELATION, CONNECTORS PIVOTALLY CONNECTING ADJACENT PAIRS OF BARS, SAID BARS HAVING REGISTERING PASSAGES THERETHROUGH EXTENDING LONGITUDINALLY OF THE GRID, HEATING MEANS EXTENDING THROUGH AND DISPOSED ENTIRELY WITHIN SAID PASSAGES FOR HEATING SAID BARS TO MELT SNOW AND ICE THEREFROM. 